Photoelectric device for recording symbols and for drawing small diagrams at high recording and drawing speed for use in an automatic drafting machine

ABSTRACT

A VIRTUALLY INERTIALESS AUTOMATIC DRAFTING MACHINE FOR RECORDING SYMBOLS AND DIAGRAMS, AT HIGH RECORDING SPEEDS, ON A PHOTOGRAPHIC LAYER. AN ADJUSTABLE ILLUMINATING SYSTEM PRODUCES AN IMAGE OF A LINE-THICKNESS-DETERMINING APERTURE, THE IMAGE BEING DIRECTED TO A PAIR OF ROTATABLE MIRRORS SO THAT IT IS DEFLECTED IN A DIRECTION OF ONE OR THE OTHER COORDINATES AND ONTO THE PHOTOGRAPHIC LAYER, THE MIRRORS BEING CONTROLLED BY SIGNALS SUPPLIED BY A STORAGE MEDIUM.

March 20, 1973 K B. KUTTIGEN E Al 3,721,164

' PHOTOELECTRIC DEVICE FOR RECORDING SYMBOLS AND FOR DRAWING SMALL DIAGRAMS AT HIGH RECORDING AND DRAWING SPEED FOR USE IN AN AUTOMATIC DRAFTINGMACHINE Original Filed Feb. 6. 1969 2 SheetS-Sheet l PHOTOELECTRIC DEVICE FOR REC DING SYMBOLS AND =FOR DRAWING March 20,1973 K-B. KUTT EN 4- SMALL 'DIAGRAMS AT HIGH RECORDING AND DRAWING SPEED I FOR USE IN AN AUTOMATIC DBAFTING MACHINE Original Filed Feb. 6. 969 2 Sheets-Sheet 2 iii/n7,

US. Cl. 95-1 R 10 Claims ABSTRACT OF THE DliSClLOSURE A virtually inertialess automatic drafting machine for recording symbols and diagrams, at high recording speeds, on a photographic layer. An adjustable illuminating system produces an image of a line-thickness-determining aperture, the image being directed to a pair of rotatable mirrors so that it is deflected in a direction of one or the other coordinates and onto the photographic layer, the mirrors being controlled by signals supplied by a storage medium.

This is a continuation of application Ser. No. 796,981 filed Feb. 6, 196 9.

The present invention relates to a photoelectric device for use with an automatic drafting machine.

Drafting machines that have recently become known are capable of applying drawings and letterings on a drawing sheet or other support according to signals supplied by a punched tape or other storage medium. For this purpose, the automatic drafting machine is provided with an operating head or operating carriage displaceable in the direction of two coordinates, a tool provided on the operating carriage or operating head applying the required symbols, for example characters, numbers and/or drawings by recording, drawing, engraving, cutting or the like.

Since in automatic drafting machines of this kind comparatively substantial masses, from the driving motors to the tool, have to be moved for the recording or the drawing operation, and since, moreover, at least some of the driving motors are mounted on the masses to be moved, comparatively long starting and braking distances have to be taken into account, so that particularly small diagrams and symbols with short lines can be supplied to the drawing sheet or other support only at comparatively low average recording and drawing speeds. Upon starting and braking of the masses to be moved, deformation of individual parts with resultant falsification of the required symbols and drawings is to be expected, particularly when the symbols and drawings are somewhat complicated and have to be applied quickly to the drawing sheet or other support. The fact that automatic drafting machines of this kind are worn particularly upon starting and braking, whereas continuous operation does not result in any appreciable wear, is a further important factor by which the efficiency is aiiected, so that for this reason also, the application of small lines and complicated symbols to the drawing sheet or other support is impaired.

Automatic drafting machines are known in which the lines and symbols are applied by photoelectric means to a photographic layer instead of being applied by a recording mechanism to a drawing sheet or other support. in these known photoelectric drafting machines, in which there is no Working resistance of the tool, the recording and drawing operations necessitate the movement of masses and the aforementioned disadvantages still persist, if perhaps to a slightly reduced extent.

ted States Patent 3,721,164 Patented Mar. 20, 1973 The invention seeks to remove these disadvantages.

According to the present invention a photoelectric device for recording symbols and for drawing small diagrams at high recording and drawing speed for use in an automatic drafting machine provided with an adjustable illuminating system, in which an image of a line-thicknessdetermining aperture of a replaceable or selectively adjustable diaphragm is reproduced on a photographic layer comprises a first image-reproducing system with telecentric path of the rays and provided with two objectives to reproduce the image of the aperture of the replaceable or selectively adjustable diaphragm at an aperture in an intermediate diaphragm located at the rear focus of the second objective of the first image-reproducing system, a second image-reproducing system with telecentric path of the rays and also provided with two objectives, the front focus of the first objective of this second image-reproducing systern is located at the aperture of the intermediate dia-' phragm, the rear focus of the second objective of this second image-reproducing system being located in the photo-' graphic layer, to reproduce the image produced in the aperture of the intermediate diaphragm on the photo graphic layer, and a pair of rotatable mirrors located one each at the rear focus of the first objective and the front focus of the second objective of the respective image-reproducing systems to deflect a light beam in a direction of one or other co-ordinate, the mirrors being controlled by signals supplied by a storage medium.

In such a photoelectric device a working carriage of the automatic drafting machine does not move at all when symbols, such as characters, numbers and diagrams consisting of short lines are applied to the photographic layer, so that virtually no masses at all have to be accelerated or decelerated. The virtually inertialess device has thus an unlimited recording and drawing speed. The aforemen tioned disadvantages thus cease to exist. Since this photoelectric apparatus is mounted on the working carriage of the drafting machine, lines of any length may be applied to the photographic layer simply by shifting the working carriage.

The invention will be described further, by way of example, with reference to the accompanying drawings in which:

FIG. 1 illustrates optical elements of a photoelectric device mounted on a work carriage of an automatic drafting machine, for recording symbols and for drawing small diagrams at high recording and drawing speed, in which the holders and the bearing are omitted;

FIG. 2 illustrates an image of a diaphragm projected upon an intermediate diaphragm without deflection and with a deflection in the direction x;

FIG. 3 illustrates an image of a diaphragm projected upon a photographic layer without deflection, with deflection in direction x and with deflection in direction v;

FIG. 4 illustrates means for driving the supports of two mirror galvanometers of the photoelectric device il lustrated in FIG. 1, and

FIG. 5 illustrates a modified construction of the driving means for the supports of the two mirror galvanometers of the photoelectric device shown in FIG. 1.

A photoelectric device for recording symbols, such as characters, numbers, mathematical or geometrical symbols and for drawing small diagrams at high recording and drawing speed is controlled, in a manner known per se, by a punched tape or other storage medium, for example a magnetic tape. The device comprises a light source 1 having a concave reflector 2 for increasing its illuminating power. A xenon arc serves advantageously as the light-source l. A condenser lens, comprising two optical elements 3:: and 3b, forms an image of the light source 1 at an aperture in an intermediate diaphragm 4.

An adjustably movable condenser and a selective mirror 6 reproduce the image of the aperture in the intermediate diaphragm 4 at an aperture in a replaceable or adjustable diaphragm 7. In FIG. 1, the diaphragm 7 is rotatable by means of a servo-motor 7a. The selected aperture of the rotatable diaphragm 7 determines, in the manner hereinafter described, the line thickness of the symbols to be recorded or of the diagrams to be drawn. The smallest desired line thickness requires, for known reason, a substantial amount of light, whereas the maximum line thickness requires correspondingly less light. The condenser 5, which is displaceable by means of an electric servo-motor (not shown) through a rack-and-pinion drive 50, 5b, may be displaced so that the beam of light illuminating the aperture of the diaphragm 7 is convergent or divergent with the result that only the selected aperture of the diaphragm 7 is illuminated, that is to say fully illuminated, at a time. In order to enable positioning of the start and finish of lines and in order to regulate the intensities of the line-producing beams of light according to the respective recording or drawing speed and according to the diameter of the selected aperture of the diaphragm 7, a shutter 8 operated by an electric servo-motor 8a is provided between the element 3b of the condenser 3a, 3b and the intermediate diaphragm 4, and a neutral wedge filter 9 displaceable in a guide 9a is provided between the intermediate diaphragm 4 and the movable condenser 5. The servo-motor 7a of the rotatable diaphragm 7 and the servo-motor 8a of the shutter 8 are fed with regulating signals by a punched tape or other storage medium. The neutral wedge filter '9 is moved in its guide 9a by means of a servo-motor (not shown) through a rack-and-pinion drive 9b, 9c. The selective mirror 6 reflects the shortwave light used for illuminating the selected aperture of the diaphragm 7 and thus for illumination of the photographic layer, whilst the long-wave portion of the light passing through the mirror 6 falls upon a photoelectric cell 10, the output current of which controls the servo motor of the neutral wedge filter 9.

A first image-reproducing system with telecentric path of the rays and a second image-reproducing system with telecentric path of the rays reproduce the image of the fully illuminated aperture of the rotatable diaphragm 7 in its original size on a photographic layer S. Only the central beams of light of these image-reproducing systems are shown in the drawing. The first image-reproducing system comprises a first objective 11, the front focal plane of which is disposed exactly in the plane of the rotatable diaphragm 7. The first objective 11 forms beams in which the peripheral rays extend parallel to their axis and in which the axes converge in its rear focus. The light transmitted by the objective 11 falls on a first deflecting mirror 13 and then on a mirror 14 of a mirror galvanometer (not shown). The mirror 14 is rotatable about an axis 14a extending at right angles to the photographic layer S and parallel to the axis 12 of the light beam passing through the objective 11. The axis 14a is arranged at the rear focal plane of the objective 11. The still parallel beam of light is reflected by the mirror 14 of the mirror galvanometer to fall on a second deflecting mirror 13a and thence to a further deflection mirror 15. The light beam then falls in a second objective 16 of the first imagereproducing system. The second objective 16 produces a convergent beam of light, which is reflected by a mirror 17 into an aperture in an intermediate diaphragm 18. The front focus of the objective 16 is disposed at the axis 14a of the mirror 14 of the mirror galvanometer and its rear focus is disposed at the plane of the intermediate diaphragm 18 thus resulting in an image of the aperture in the diaphragm 7 being reproduced in its nautral size at the aperture in the intermediate diaphragm 18. The first image-reproducing system causes the image of the aperture in the rotatable diaphragm 7 to move on the photographic layer S in direction x. A second image-reproducing system of analogous construction causes the image of the aperture of the rotatable diaphragm 7 to move on the photographic layer S in direction v. The divergent beam of light issuing from the aperture in the intermediate diaphragm 18 is reflected by a mirror 19 to a first objective 20. The front focal plane of the objective 20 is disposed in the plane of the intermediate diaphragm 18. A parallel beam of light emerges from the objective 20 but in which the axes converge in the rear focus of the objective 20. The beam of light is reflected by a deflecting mirror 22 and a deflecting mirror 23 on to a mirror 24 of a mirror galvanometer (not shown) the axis 24a of the mirror being perpendicular to the photographic layer S and parallel to the axis 21 of the central beam of rays, and the rear focus of the objective 20 being disposed at the axis 24a. The beam of light reflected by the mirror 24 is reflected by a deflecting mirror 23a on to a second objective 25 whose front focus is disposed at the axis 24a of the mirror 24, and whose rear focus is disposed at the photographic layer S. The objective 25 thus produces on the photographic layer S an image of the image at the aperture of the intermediate diaphragm 18, that is to say an image of the image of the aperture in the rotatable diaphragm 7. In FIG. 1 the mirrors 23, 23a and 24 are turned through an angle of about the axis 21 in order to provide a clear representation.

At the commencement of the work, the work carriage of the automatic drafting machine is moved by signals supplied by the punched tape or other storage medium to a position in which the photoelectric device provided thereon is exactly above the position of the photographic layer S to which a symbol or a diagram is to be applied. It will be appreciated that when lines are to be drawn, the same difliculties as those encountered in other photographic recording apparatus have to be overcome.

The intensity of illumination required is determined by the required line thickness and the magnitude of the recording or drawing spee'd required at the time, which amounts to v /v +v This is achieved as follows:

"Control signals supplied by the punched tape or other storage medium adjust the diaphragm 7 according to the required line thickness and the movable condenser 5 according to the selected aperture of the diaphragm 7. The light source 1 is switched on and the long-wave portion of the light passes through the selective mirror 6 to fall on the photoelectric cell 10. The current produced by the cell actuates the servo-motor to move the neutral wedge filter 9 in its guide 9a by way of the rack-and-pinion drive 9b, 9c. The intensity of illumination is thus adjusted to the required recording or drawing speed and, if desired may also be adjusted to the required line thickness. The recording or drawing is effected by signals supplied by the punched tape or other storage medium, the signals acting upon the mirror galvanometers, so that the mirrors 14 and 24 thereof are rotated in such manner as to cause deflection of the image of the adjusted aperture of the diaphragm 7 on the photographic layer S, such deflection producing the recording or the drawing operation. The beginnings and the ends of the lines are positioned by a shutter 8 which is also controlled by signals supplied by the punched tape or other storage medium.

In FIG. 2, the reference numeral 26 represents an undeflected image of the aperture in the diaphragm 7 in a rectangular system of coordinates x and y, the reference numeral 26' representing an image deflected in direction x. FIG. 3, again, shows the undeflected image 26 of the diaphragm 7, whilst the reference numeral 26 represents the image deflected in direction x, and 26 represents the image deflected in directions x and y. Since the mirrors 14 and 24 of the two mirror galvanometers are rotated by the signals supplied by the punched tape or other storage medium, independently of each other, successively or simultaneously, straight lines extending in any direction and lines of any curvature may be applied by the photoelectric device to the photographic layer S.

The deflecting mirrors 13, 13a, 15, 17, 19, 22, 23 and 23a do not affect the reproduction of the image of the aperture of the diaphragm 7 on the photographic layer S and may be arranged differently, or, if desired, some of the deflecting mirrors may even be omitted, according to the construction of the photoelectric device.

In order to enable the photoelectric device to be used for recording or drawing symbols or diagrams in a rectangular drawing system extending at an angle to the coordinates of the drawing board of the automatic drafting machine, the two mirror galvanometers, of which only the mirrors 14 and 24 are shown the mirrors 13 and 13a, 23 and 23a are respectively mounted on supports 14b and 24b as shown in FIG. 4, the supports 14b and 24b being respectively mounted so as to be rotatable on shafts 14c and 240 coaxial with axes 12 and 21 of the beams of rays. Each support 14b and 24b carries a pinion 14d and 24d respectively. The pinions 14d and 240! mesh with a pinion 27 driven by a servo-motor (not shown) provided with a check-back position indicator.

The signals for controlling the servo-motor of the pinion 27 and thus the adjustment of the system of coordinates x and y of the photoelectric device in relation to the system of coordinates x and y of the drawing board of the drafting machine are generally supplied by a punched tape or other storage medium. The photoelectric device can start to operate after adjustment of the mirror galvanometer by the servo-motor through the pinion 27, and after the positions of the mirrors 14 and 24, 13 and 13a and 23, and 23a have respectively been checked by the check-back position indicator of the servo-motor.

When the photoelectric device is to be used for recording symbols or for drawing diagrams in an oblique-angled coordinate system, means have to be provided, so that the directions of the coordinates x and y of the photoelectric device may be varied in relation to those of the drawing board of the automatic drafting machine. As illustrated in FIG. 5, the mirror galvanometer causing the deflection of the image of the aperture of the diaphragm 7 to the photographic layer S in direction x (only the mirror 14 of the mirror galvanometer is shown in FIG. is for this purpose, mounted on a support 14b which is mounted so as to be rotatable on a shaft 140 coaxial with the axis 12 of the beam of rays. Mounted on the support 14b is a pinion 14d which meshes with a pinion 27a driven by a servo-motor (not shown) provided with a check-back position indicator. The mirror galvanometer, of which only the mirror 24 is shown in FIG. 5, which causes the image of the aperture of the diaphragm 7 to be deflected on the photographic layer S in direction y is mounted in the same manner on a support 241) which is mounted so as to be rotatable on a shaft 24' coaxial with the axis 21 of the beam of rays. Mounted on the support 24b is a pinion 24d which meshes with a pinion 27b driven by a servo-motor (not shown) provided with a check-back position indicator.

In this construction also, the signals for adjusting the servo-motors and thus for adjusting the directions of the coordinates x and y of the photoelectric device in relation to the system of coordinates x and y of the drawing board of the automatic drafting machine are usually supplied by a punched tape or other storage medium. The photoelectric device can start to operate when the mirror galvanometers have been adjusted accordingly by the servo-motors through the pinions 27a and 27b according to the oblique-angled coordinate system of the photoelec tric device, and when the adjustments of the mirrors 1d and 2 1 have been checked by the check-back position indicators of the servo-motors.

It will be understood that it is possible to change the scale of signals given to the mirror galvanometer 14 and to the mirror galvanometer 24 since such two mirror galvanometers are activated independently.

It will be understood that in the construction illustrated in FIG. 5 it may also be arranged that one of the servomotors adjusts, for example, the position of the coordinate direction x of the photoelectric device in relation to the direction of the coordinate y thereof, and the other servo-motor adjusts the position of the oblique-angled coordinate system of the photoelectric device in relation to the rectangular coordinate system of the drawing board of the automatic drafting machine instead of the directions of the coordinates x and y of the photoelectric device being adjusted independently of each other by the servo-motor through the pinions 2 7a and 27b.

Since the signals causing the photoelectric device to record the required symbols or to draw the desired diagrams, are taken from a store which generally has a limited holding capacity, various measures may be taken to ensure the recording of the maximum number of symbols and the drawing of the maximum number of diagrams with a comparatively small number of storage locations.

Thus, for example, the ratios or transmissions between the supplied signals for deflection of the image of the aperture of the diaphragm 7 in directions x and y may be adjusted separately. This enables the photoelectric device to record a symbol or to draw a diagram of a given width at different levels.

Symbols or diagrams may also be plotted at an angle according to signals suplied by the punched tape; for example, they may be inclined in direction x, in the direction of recording and in the direction y.

Symmetrical symbols and diagrams may be produced with the same storage locations by changing the sign of the control signals for the mirror galvanometers according to the signal supplied by the punched tape.

What is claimed is:

1. A photoelectric device for recording symbols and for drawing small diagrams at high recording and drawing speed for use in an automatic drafting machine provided with an adjustable illuminating system, in which an image of a line-thickness determining aperture of a replaceable or selectvely adjustable diaphragm is reproduced on a photographic layer comprising:

a first image reproducing system having a first objective and a second objective, said first and second objectives reproducing an image of the aperture in the re placeable or adjustable diaphragm in a given plane located at the rear focus of said second objective of said first image reproducing system;

a second image reproducing system having two objectives, the front focus of the first objective of the second image-reproducing system being located at said given plane, the rear focus of the second objective of this second image-reproducing system being locatable in a photographic layer;

and a pair of rotatable mirrors located between the first and second objectives of the respective image-reproducing systems to deflect a light beam for the purpose of drawing lines in a direction of one or other cordinate, the mirrors being controlled by signals supplied by a storage medium.

2. A photoelectric device as claimed in claim 1 in which each of the two mirrors is mounted on a support which is rotatable on a shaft coaxial with the optical axis of the respective image-reproducing systems, each support being driven by a servo-motor controled by signals supplied by a storage medium.

3. A photoelectric device as claimed in claim 1 in which each of the two mirrors is mounted on a support so as to be rotatable on a shaft coaxial with the optical axis of the respective image-reproducing systems, each support being driven by separate servo-motors which are controlled by signals supplied by a storage medium.

t. A photoelectric device as claimed in claim 1 in which a separate device for varying the scale of the signals supplied by the storage medium is arranged in front of each of the mirrors, said devices being controlled by the signals supplied by the storage medium.

5. A photoelectric device as claimed in claim 2 in which a separate device for varying the scale of the signals supplied by the storage medium is arranged in front of each of the mirrors, said devices being controlled by the signals supplied by the storage medium.

6. A photoelectric device as claimed in claim 3 in which a separate device for varying the scale of the signals supplied by the storage medium is arranged in front of each of the mirrors, said devices being controlled by the signals supplied by the storage medium.

7. A photoelectric device as claimed in claim 1 in which a device for varying the sign of the signals supplied is arranged in front of each mirror, the device being controlled by signals supplied by the storage medium.

8. A photoelectric device as claimed in claim 2 in Which a device for varying the sign of the signals supplied is arranged in front of each mirror, the device being controlled by signals supplied by the storage medium.

9. A photoelectric device as claimed in claim 3 in which a device for varying the sign of the signals supplied is arranged in front of each mirror, the device being controlled by signals supplied by the storage medium.

10. A photoelectric device as claimed in claim 1 having References Cited UNITED STATES PATENTS 2,600,168 6/1952 Klyce -45 2,724,310 11/1955 'P'aine 95-13 3,103,849 9/1963 Wise 95-12 3,247,761 4/1966 Herreman et al. 95--12 3,537,364 11/1970 Pabst 951 R 3,648,578 3/1972 Ritchie 9512 3,648,583 3/1972 Blattner 9512 $595,147 7/1971 Blattner 9512 RICHARD L. MOSES, Primary Examiner U.S. Cl. X.R. 9 -12 

